L3301 front hydraulics leaking after warranty work

[Scott65]

I'm not usually the type of person to have work done, then after the fact start nit picking every little thing and claim "it wasn't doing that before, it's something you did". I'm a mechanic, I have customers like that so I know what it feels like. Having said that, I have a 2013 Kubota L3301 HST that was leaking from the seam between the trans (or what would otherwise be?) and the rear diff housing. I had it done at the local dealer. When they split it, something occurred internally: The day I went to pick it up, the tractor backed out of the work stall about 15 feet and went forward about 20 and then stopped moving. Several working days later I got it back, story was that a snap ring must have gotten stressed when the case was split, then let go and the shaft unsplined. I'm ok with that... I wasn't too happy the day it happened that the mechanic told me he was going to collect and reuse all the new fluid he had poured in it, after I had just paid $100 for the 2 hydraulic filters that the warranty wasn't covering.

So here's my issue. The tractor has 280ish hours on it, meticulously maintained mechanically (sure, she has some bruises). I've added a grapple of my own making to the front loader, at probably 50-100 hours. The hydraulics would hold the tractor off the ground overnight. Maybe for weeks, I don't really know. In other words, they held really well. This includes the loader, grapple, and 3 point. The day after getting it back from this dealership incident, I notice an incessant popping sound that is oh so familiar. Sounds just like one of my automotive lifts that creeps. Sure enough, it won't hold the bucket off the ground, or even the grapple open over night. If any load at all in the bucket, it will creep down even as I'm working. The 3 point seems ok but I've not had a big load on it yet. So, is this something in the back, like the power beyond circuit that they pulled loose? Some junk stuck somewhere from recycling the fluid that I've always paid so dearly to keep replaced with brand name clean stuff? Or is there even any way it's related at all, just coincidence? I'm not too high and mighty. I'll admit, I made a scene about the transmission breakage (for other reasons). But if it's unrelated, I'll swallow the cost and fix it on my own. I just don't know all the possibilities to cause this sort of leak.

Thanks in advance

 

[J_J]

I believe your attachments hyd is not related to the transmission leak.

If the leak is the hyd tank that holds all hyd fluid, then that may be related.

Your hyd flow path might be something like this.

Pump , hyd blk out to FEL IN port, FEL PB port to hyd blk, remote valve if you have one or 3pt, then tank.

 

[Scott65]

The leak won't be related to the original leak, in itself. But rather the work done when repairing said leak. The "tank" for the hydraulic fluid is the case itself on this tractor. It uses the same fluid for the FEL/3 point hydraulics and the HST transmission. I don't have any external leaks that I've seen so far. I just have a leakdown on the FEL and grapple circuits, all of them. The way I have it plumbed, it comes off the pump, to the FEL control which contains the pressure control, then the power beyond goes straight to the grapple valve that I've mounted using the same bolts that hold the FEL joystick valve. Then down to the hydraulic block under the "passenger side" foot step, then back to the diff housing to feed the 3 point. So they would have pulled loose a certain amount of the plumbing where it goes into the rear housing feeding to the 3 point. I am completely unfamiliar with any of this part of the system. Is there anything in that back part that is necessary that, if leaking now, could cause all of the circuits up front to start creeping down? I originally thought that it would be contained in the FEL valve, but it just seems odd that all of a sudden its leaking so badly. The alternative (if its all related) is that when he recycled the fluid, it was dirty and now has junk stuck in the valve somewhere